Open resection of ascending aneurysms and in particular aortic dissections, carries a high mortality. In type A dissections, the mortality with open repair may reach up to 25%, many patients dying from bleeding complications or cerebral complications associated with using deep hypothermic circulatory arrest (DHCA). The friability of the tissues in these patients is a significant challenge when reconstructing and sewing a graft to the distal ascending aorta and the proximal arch, which in turn increases the duration of DHCA and therefor the complication and mortality rates. Type A dissections typically start in the ascending aorta and propagate distally delaminating the wall of the aorta causing a chronic weakness in the wall that in many cases degenerates into an aneurysm. The intimal flap creates 2 or more pathways of flow called the true (TL) and false lumen (FL). These conditions are effectively treated by surgical resection and replacement of the ascending aorta. However, the delaminated wall of the aorta is typically untreated because of the high risk associated with the additional resection of the aorta distal to the ascending segment. Additionally, the aortic arch of a patient may have variation in size, dimensions and the like. Use of stent portions for being received within the arch are thus constrained by the variations among different aortic arches.
Acute aortic dissections and intramural hematomas (IMH) are caused by an intimal tear or hemorrhage within the aortic wall. This causes delamination and propagation of the intimal flap proximally and distally. The proximal propagation of the intimal flap can cause aortic insufficiency, blockage of coronary arteries, aortic rupture and death. This is prevented by surgical replacement of the ascending aorta. Distal propagation of the intimal flap can cause blockage of important aortic side branches leading to stroke or visceral malperfusion. Typically the pressurized and perfused FL expands and causes the compression of the TL. During the acute phase of the dissection process, the tear causes inflammation of the aortic wall. If the intimal flap is reattached and supported, the inflammation will help in fusing the dissected layers and potentially allow the dissection to cure. This will encourage positive aortic remodeling and exclusion/depressurization of the FL.
Although the technique of ascending aortic replacement has been perfected, currently there are no effective means of reattaching the dissected intimal flap to the aortic wall in the arch and beyond. To address the long term complications attributed to the FL, different devices have been designed but none have been shown to be effective. In addition, some surgeons advocated for additional resection of the aortic arch during the index operation, however the majority of surgeons are reluctant to do so due to an increase in the complexity of the operation and the mortality. Additionally, resection of the arch will not exclude the FL in the remainder of the aorta. The endovascular solutions available for treatment of aortic aneurysms are inadequate for treatment of dissections because their graft coverage fixes their diameter and won't allow for the device to expand freely to re-attach the intimal flap. In addition, the graft coverage will obstruct important aortic side branches perfusing the brain, spinal cord and viscera.
The above challenges may be overcome by the invention disclosed in this application, where the proximal reinforced section of the graft allows for a more secure and hemostatic suture line, the distal stent reinforced graft section allows for future landing zone to implant additional endografts and the intervening braided, uncovered stent portion allows tacking and stabilizing of the aortic tear and the detached intima to the remainder of the aorta without compromising blood flow to the supra-aortic branches, thereby excluding the FL and providing an opportunity for the tear to heal and to cure the dissection.